Two South Korean F-15K fighter jets escorted the bombers as they flew west over the base, swooping just 450-500 meters above the ground at one point.

"Their altitudes were so low that they were seen well from the stands, and not only the roar, but even a little vibration was also felt that spectators gaped at them," a defense ministry official said.

The bombers entered South Korean airspace after taking off from Anderson Air Base in Guam earlier in the day.

SHOW OF FORCE: The bombers flew over South Korea on Saturday as part of an air show (Image: YONHAP)

WAR DRILL: A US Air Force B-1B Lancer bomber flying with South Korean jets (Image: GETTY)

The flight comes just 11 days after the US flew two B-1B bombers took part in a surprise military drill off the coast of North Korea.

A total of six military planes – including the two US B-1B bombers – took part in the show of force amid fears Kim Jong-un's regime is gearing up to launch another nuclear missile.

North Korean state media has lashed out at the "chief criminal" US for holidng provocative war drills in the region.

State owned newspaper Rodong Sinmun said such "sabre rattling" could “ignite a nuclear war” in which North Korea “annihilate the US imperialist aggressors".